This invention relates to a method for the stabilization of slopes and/or terrain which are unstable or subject to landslides, by inserting suitable drainage devices.
In particular, a vertical shaft with a concrete lining or a microtunnel is constructed in an area of ground predefined by a suitable geological study, and an automated drilling unit is positioned in the microtunnel or vertical shaft.
Said drilling unit comprises at least one drilling head, a magazine of rods, and robotic devices able to pick up the rods from the magazine and take them to said drilling head, said rods being constituted by said drainage pipes; said head is then controlled to perform drilling operations, with simultaneous laying of the drainage pipe.
In accordance with an advantageous aspect of the invention, said drainage pipes are constituted by a tubular steel element, the walls of which contain holes, each of which said holes houses a microfiltration valve. Said holes are filled with water-soluble material to prevent the passages from becoming obstructed during drilling; when the pipe has been laid, the water-soluble material dissolves, thus clearing said passages.
In this way, drainage pipes can be laid directly in unstable terrain in a fully automatic manner, with no need for the operators to access the terrain, and therefore with no risk to them.
In this patent application, and in particular in the claims, the term “shaft” is used to indicate both a vertical shaft and a microtunnel.
In order to stabilize slopes affected by surface phenomena or actual gravitational movements of the mass, suitable devices are often installed to drain off the water circulating in the mass of debris.
Technologies known according to the state of the art involve the construction of drainage trenches, sub-horizontal drains, drainage tunnels or drainage shafts.
These technologies require a major investment in human and material resources, and are therefore very expensive. Drainage systems are also known which involve inserting in the ground drainage pipes consisting of metal or plastic pipes containing holes for the passage of water.
A number of said drainage pipes are inserted into the ground up to the required depth, spaced at a suitable distance apart.